Evaluate in Subsession
Evaluate in Subsession evaluates the selected cells in a kernel dialog.
When an evaluation is in progress, you can use this command to inspect the state of the kernel. When you select Evaluate in Subsession, the current evaluation is suspended (indicated by a grayed cell bracket), the cells selected are evaluated in a kernel subsession (Dialog), and then the original evaluation is resumed.
This can be useful for checking on the status of variables in a long calculation or for debugging.
See Reference Guide: Dialog.